In combination with personal computers (PCs) for point of sale (POS) applications, special periphery for POS applications is used. That periphery connects to the PC via a specific powered USB cable. When using devices without internal power supply unit or without specific powered USB port, e.g. when using so-called tablet computers, such a periphery is operated via an external powered USB host adapter, if needed. That periphery either has a 12 V or a 24 V supply voltage. The powered USB industrial standard is described in the document “Retail USB, USB PlusPower, USB+Power—Electro-Mechanical Specification, Version 0.8g”, for example. Compared to conventional USB ports, powered USB ports comprise additional contacts for power supply of powered USB peripheral devices.
In this context, one problem lies with the fact that the powered USB periphery requires high peak power in operation. The power supply units of conventional PC standard systems, in particular so-called thin clients, are not configured to additionally support the peak power of the powered USB devices. When using external powered USB host adapters, dimensioning for the peak power leads to lower energy efficiency, at least during operation with a much lower power.